Coated articles are known in the art for use in window application such as insulating glass (IG) window units, vehicle windows, monolithic windows, and/or the like. It is known that in certain instances, it is desirable to heat treat (e.g., thermally tempered, heat bent and/or heat strengthened) such coated articles for purposes of tempering, bending, or the like.
In certain example instances, designers of coated articles often strive for a combination of high visible transmission, substantially neutral color, low emissivity (or emittance), and low sheet resistance (Rs). High visible transmission and substantially neutral color may permit coated articles to be used in applications where these characteristics are desired such as in architectural or vehicle window applications, whereas low-emissivity (low-E) and low sheet resistance characteristics permit such coated articles to block significant amounts of IR radiation so as to reduce for example undesirable heating of vehicle or building interiors. In certain example instances, low U-values are also desired.
However, heat treatment of coated articles typically requires use of temperature(s) of at least 580 degrees C., more preferably of at least about 600 degrees C. and still more preferably of at least 620 degrees C. The use of such high temperatures (e.g., for 5-10 minutes or more) often causes coatings to break down and/or causes one or more of the aforesaid desirable characteristics to significantly deteriorate in an undesirable manner. For example, thermal tempering of certain coated articles may cause color and/or visible transmission to shift to an undesirable value that may be aesthetically and/or functionally displeasing.
In view of the above, it will be apparent to those skilled in the art that there exists a need for coated articles which are capable of providing high visible transmission, substantially neutral color, low emissivity (or emittance), and/or low sheet resistance (Rs). In certain example embodiments, it may be desired that one or all of these characteristics can be achieved even after the coated article has been heat treated.